1. Technical Field
The present disclosure relates to a surgical stapling apparatus. More particularly, the present disclosure relates to an endoscopic surgical stapling apparatus including a mechanism for retracting the actuation shaft of a surgical stapling apparatus.
2. Background of Related Art
Surgical devices capable of fastening tissue portions are well known in the art. Some of these devices include a knife to cut the tissue that has been joined by the fasteners. Although the fasteners are typically in the form of surgical staples, two-part polymeric fasteners may also be employed.
Surgical fastening instruments can include two elongated jaw members used to capture or clamp tissue. One jaw member typically contains a staple cartridge that houses a plurality of staples arranged in at least two lateral rows while the other jaw member has an anvil that defines a surface for forming the staple legs as the staples are driven from the staple cartridge. The stapling operation is usually effected by cam members that translate through the staple cartridge, with the cam members acting upon staple pushers to sequentially eject the staples from the staple cartridge. A knife may move axially between the staple rows to cut or open the stapled tissue between the rows of staples. U.S. Pat. Nos. 3,079,606 and 3,490,675 disclose examples of this kind of instrument.
A stapling apparatus disclosed in U.S. Pat. No. 3,499,591 also applies a double row of staples on each side of the incision. The patent discloses a surgical stapler having a disposable loading unit wherein a cam member moves through an elongate guide path between two sets of staggered staple carrying grooves. Staple drive members are located within the grooves and are positioned in such a manner so as to be contacted by the longitudinally moving cam member. The staple members eject the staples in the staple cartridge as the cam member moves axially along the elongate guide path. Other examples of such staplers are disclosed in U.S. Pat. Nos. 4,429,695 and 5,065,929.
Each of the instruments described hereinabove is designed for use in conventional surgical procedures wherein surgeons have direct manual access to the operative site. In endoscopic or laparoscopic procedures, however, surgery is performed through a small incision or through a narrow cannula inserted through small entrance wounds in the skin. Endoscopic surgical stapling devices have been developed to address the specific needs of endoscopic and laparoscopic surgical procedures. A few examples of endoscopic surgical stapling devices are disclosed in U.S. Pat. No. 5,307,976; U.S. Pat. No. 5,312,023; U.S. Pat. No. 5,326,013; U.S. Pat. No. 5,332,142; and U.S. Pat. No. 6,241,139, the entire contents of each of which are incorporated herein by reference.
Tyco Healthcare, LP, the assignee of the present application, has manufactured and marketed endoscopic stapling instruments, such as the ENDO GIA™ Universal and Universal XL instruments, for a number of years. See FIGS. 1-3. These instruments include a surgical stapling apparatus having a retraction mechanism to return surgical stapling apparatus to a retracted position. The retraction mechanism may include a pair of retractor knobs movably positioned along a barrel portion of a handle assembly. After firing staples, the retraction knobs may be manually pulled proximally to retract the actuation shaft of the surgical stapling apparatus to its original position. These instruments have provided significant clinical benefits. Nonetheless, improvements to these instruments are possible.
For instance, it would be extremely beneficial to provide a surgical stapling apparatus allowing a user to quickly and effortlessly retract the actuation shaft of the surgical instrument with one hand. It would also be desirable to provide a surgical stapling apparatus with a compact, simple, reliable and ergonomic powered retraction mechanism. In addition, it would be beneficial to provide a surgical stapling apparatus with a powered retraction mechanism that can be manually overridden.